diff --git a/index.html b/index.html
index 1b14729..e9efe5f 100644
--- a/index.html
+++ b/index.html
@@ -420,6 +420,7 @@ You can use this to track and report the data needed for tax reporting. Fill out
 <ul>
 <li><a href="http://www.mscs.dal.ca/~selinger/accounting/tutorial.html">Peter Selinger: Tutorial on multiple currency accounting</a></li>
 <li><a href="https://github.com/mikekchar/ledger-currencies">ledger-currencies tutorial</a></li>
+<li><a href="https://groups.google.com/d/msg/ledger-cli/dc6F-HvZOyE/5IuoxzMOBwAJ">on currency vs commodity valuation</a></li>
 </ul>
 <h5 id="shared-expenses">shared expenses</h5>
 <ul>
diff --git a/index.md b/index.md
index d0a549e..d7a25d0 100644
--- a/index.md
+++ b/index.md
@@ -452,6 +452,7 @@ Fill out and submit tax forms with another tool, or by hand.
 
 - [Peter Selinger: Tutorial on multiple currency accounting](http://www.mscs.dal.ca/~selinger/accounting/tutorial.html)
 - [ledger-currencies tutorial](https://github.com/mikekchar/ledger-currencies)
+- [on currency vs commodity valuation](https://groups.google.com/d/msg/ledger-cli/dc6F-HvZOyE/5IuoxzMOBwAJ)
 
 ##### shared expenses